Conventional brake systems includes disk brake system and caliper brake system. The disk brake system includes complicated mechanism and can brake the wheel sharply, the caliper brake system is economically manufactured and is suitable for stop wheels at slow speed. The disk brake system uses hydraulic oil to activate the brake action and the caliper brake system uses brake cables to pivot two brake pads to stop the wheel. The brake cable is connected to a yoke cable which has two ends respectively connected to two brake arms so that when the brake cable pulls the yoke cable, the two brake arms are pivoted and the brake pads on the two brake arms are move to stop the wheel. It is noted that the two brake pads cannot contact the rim simultaneously, in other words, one of the pads contacts the rim first so that the rim is applied by a force in one direction, and then the other brake pad contact the rim in opposite direction. Because at the beginning of the braking action, only one brake pad is in contact with the rim so that the speed of rim does not reduces as desired and the brake distance is therefore prolonged.
The present invention intends to provide a bicycle hydraulic brake mechanism whose brake pads are moved to stop the wheel rim simultaneously by a link mechanism which is activated by a hydraulic mechanism.